The invention relates to improvements in devices which can be utilized as drop ceilings in kitchens or similar establishments to intercept and collect liquid media (such as fat, grease and/or moisture) which are dispersed in gaseous carriers, e.g., in streams or flows of ascending air. More particularly, the invention relates to improvements in devices wherein trough-shaped collecting elements alternate with inverted trough-shaped intercepting elements for the liquid medium or media.
It is already known to assemble a set of spaced apart parallel elongated trough-shaped collecting elements with a set of inverted trough-shaped intercepting elements. The intercepting elements overlie but are spaced apart from the marginal portions of neighboring collecting elements to define therewith a plurality of paths for the flow of an ascending gaseous carrier. The liquid medium or media which are dispersed in the gaseous carrier impinge upon and are intercepted by the concave undersides of the intercepting elements and are caused to flow into and to gather along the concave upper sides of the neighboring collecting elements. The ends of the intercepting and/or collecting elements are attached to holders in the form of walls. Reference may be had, for example, to German Pat. No. 27 18 611 granted Aug. 8, 1990 to Helmut Kittler for "Separator for a room aerating and deaerating device". The intercepting and collecting elements of the patented separator resemble portions of elongated hollow cylinders each of which extends along an arc of more than 180 degrees.
European Pat. No. 0 194 527 granted Aug. 23, 1989 to Josef Hammer discloses a drop ceiling wherein the collecting elements are mounted on supports. Thus, when the collecting elements are to be cleaned to relieve them of collected liquid media (such as grease and/or fat), the supports must be cleaned at the same time. This involves additional maintenance work. The aforementioned separator of Kittler can be said to constitute a further development of the drop ceiling of Hammer in that the separator of Kittler is designed as a cassette which can be introduced into and relieved of intercepted and collected liquid media in a washing machine.
Devices of the type disclosed by Kittler and Hammer can be utilized, for example, in the kitchens of hotels and other large establishments wherein the temperature often rises to or even exceeds 40.degree. C. If a device which is designed to intercept fats, grease and/or other liquid media, (e.g., moisture) is open to permit the gaseous carrier medium to pass therethrough, even very narrow passages for the flow of gaseous carrier suffice to permit the escape of a substantial percentage of liquid media. Such liquid media thereupon rise through the openings of the support for the drop ceiling and enter the flue or flues to be admitted into the atmosphere. Moreover, the escaping liquid media rapidly contaminate the component parts of the support for the drop ceiling as well as the rails or other holders for the support. This creates numerous problems because cleaning of the supports and of the holders therefor is a tedious and time-consuming task which cannot be carried out at frequent intervals.
Another drawback of presently known drop ceilings for use in large kitchens and/or similar establishments, wherein an ascending gaseous carrier is likely to entrain dispersed liquid media, is that the collecting elements are incapable of gathering relatively large quantities of liquids so that they must be relieved of collected liquids at frequent intervals. Attempts to increase the liquid-retaining capacity of such collecting elements include the provision of separately produced end walls which are welded to the end portions of the collecting elements. The welding of end walls to the collecting elements invariably entails an undesirable discoloration of the collecting elements and adversely affects the appearance of the entire drop ceiling. Moreover, the welding operation invariably entails at least some deformation of the collecting elements, and such deformation cannot be eliminated in a subsequent step except by resorting to highly expensive remedial techniques. It is to be borne in mind that the thickness of presently used collecting elements is normally less than 1 mm.
Attempts to eliminate the drawbacks of collecting elements with welded end walls include the resort to soldering (particularly brazing) techniques. This did not alleviate the problems because the utilization of hard solder necessitates operation at elevated temperatures. As a rule, the utilization of hard solder results in pronounced deformation of the collecting elements, namely a deformation which is so pronounced that it cannot be eliminated without unduly increasing the cost of the finished products. Attempts to use soft solder also failed to solve the aforediscussed problems which arise when using hard solder or when resorting to welding because the application of soft solder must be preceded by treatment with a highly corrosive substance which ensures that soft solder will adhere to the material of a collecting element. The corrosive action of such substances is sufficiently pronounced to affect the appearance and the integrity of collecting elements, even of those made of chrome-nickel steel or other high-quality and highly expensive materials. Corrosion of collecting elements which are used in drop ceilings of large kitchens and similar establishments is not acceptable to the owners and to the authorities.